1. Inhalation stroke: the intake valve is opened, the exhaust valve is closed, and the piston moves downward from the top dead center to the bottom dead center at the same time, and the air enters the cylinder from the intake pipe.
2. Compression stroke: Both the intake valve and the exhaust valve are closed, the piston moves from bottom to top, and the air in the cylinder is compressed to 1/12-1/20 of its original volume. At the same time, the temperature rises rapidly.
3. Power stroke: the oil needle opens, and the fuel injector sprays mist diesel into the cylinder. When the diesel encounters hot air far exceeding its ignition point (350 C), it explodes immediately, and then pushes the piston to the bottom dead center, and the crankshaft output power.
4. Exhaust stroke: the exhaust valve is closed and opened, and the piston moves upward at the same time, and the exhaust gas is discharged from the exhaust pipe.
5. After the exhaust stroke is completed, the exhaust valve is closed, the intake valve is opened, the piston moves downward, and a new suction stroke is started to enter the next cycle.